You'll unlikely be surprised by many of the items in their list, but that doesn't make them any less true. The article highlights, for example, the rebate trap:

Department and electronics stores often advertise goods at post-rebate prices, assuming most customers will be too lazy to mail in the rebate, which could save them up to 10% on big-ticket items such as dishwashers, refrigerators and computers. At Staples, a $650 laptop from Hewlett-Packard carries a $50 rebate. Don't let them get away with this. Filling out and mailing the rebate takes all of 15 minutes. Says Tod Marks, senior project editor at Consumer Reports: "Anyone who walks away from rebates is giving money away."

Apart from the rebates, the author also highlights the following as expensive outcomes of a little financial laziness:

Not Choosing the Best Rate on Your Savings Account

Not Opening a Retirement Fund (As Soon As Possible)

Not Paying Attention to 0% Financing Deadlines

Waiting Until the Last Minute to Send Mail

Not Taking Advantage of Corporate Wellness Incentives

Not Bothering to Negotiate a Better Deal

Oversleeping (But Not for Reasons You May Think)

Hit up the full article for their full explanation behind why each course of inaction is costing you cash, and let us know about times your laziness took you to the bank (late DVD rentals, forgetting to move your car to the other side of the street?) in the comments.